Understanding material selection trends and complying with the needs of governing regulatory agencies is fundamental to success in medical device production. As manufacturers set development objectives, they consider material characteristics, such as ease of processing, performance, and aesthetics. These organizations constantly seek to improve the material selection in order to boost production and cost efficiencies. This provides material suppliers with a unique opportunity to work in collaboration with medical device manufacturers to deliver a more superior product to healthcare professionals, which ultimately benefits patients.

Fig. 1 – Microspec’s ability to extrude advanced medical tubing with complex shapes and many lumens makes it possible to accomplish more in a single device. Within one tube, the lumens may vary in shape, size, number, symmetry, shaft diameter, durometer hardness, wall thickness and web thickness, among other physical attributes. Pictured here are multi-lumen tubes manufactured using SBCs.

As organizations seek to identify ideal material solutions, the innovative quality of a supplier’s products, as well as deep expertise in healthcare regulations are essential for success.

Styrenics Offer Distinct Performance Advantages for Flexible Medical Tubing

Microspec Corporation, Peterborough, NH, has earned a global reputation for extruding the most complex tubing in the industry. The company sought to develop multi-lumen tubing to administer different medicines from one central access point. Since lumens vary in shape, number, symmetry, and diameter, Microspec required an alternative material with unique processing properties to create the intricate tube structure. Additionally, the material had to meet strict regulatory requirements and offer long-term use and formulation guarantees for Microspec. (See Figure 1)

A Unique Resin Mixture Offers the Ideal Properties

Microspec selected two styrene butadiene block copolymers (SBCs), from Styrolution, Aurora, IL, because of their ease of processing and low drug absorption rates. However, to help Microspec reach the specific shore hardness they aimed to achieve, Styrolution helped develop a unique mixture of Styroflex and Styrolux. The enhanced processability of the mixture enabled the production of a more complex lumen structure, which provided optimal tube stabilization when inserting guide wires or rigid tubes.

The styrenic materials also delivered other advantages, such as a low yellowness index, increased clarity vs. other materials, better run rates, and the elimination of material migration. In addition, there was a density advantage of 20 to 30 percent when compared to other materials that Microspec had evaluated. (See Figure 2)

Additionally, an additive was used that successfully eliminated blocking and reduce the coefficient of friction properties in the tubing. These resins gave Microspec the opportunity to further strengthen its leading position in multi-lumen tubing, as evidenced by highly positive market feedback the company received. (Editor’s Note: Microspec’s advanced 28 lumen tubing was spotlighted in an article in the March issue of Medical Design Briefs, www.medicaldesignbriefs.com/component/content/article/1105-mdb/features/21704 .

SBC Resins Offer Endless Possibilities for Future Medical Applications

Fig. 2 – This picture illustrates a 28 lumen tube produced by Microspec.

Both Styroflex and Styrolux possess the properties of a thermoplastic elastomer (S-TPE). One resin is particularly well suited to the extrusion process used for applications, such as medical tubing. (See Figure 3)

The material is characterized by a combination of high resilience, toughness, optical clarity and processability, offering good printability and adhesion to many different polymers. It is also employed as a high-performance additive to increase toughness and stress cracking resistance. In the future, SBCs such as this may serve as ideal material solutions for IV, collection and blood bags.

The other resin offers high transparency, brilliance and impact resistance and can be extruded, thermo-formed, and injection molded into a variety of high-quality products including medical drip chambers and connectors.

Ensuring Regulatory Compliance

Fig. 3 – Transparent multilumen tubing manufactured by Microspec.

Among the key reasons Microspec selected these particular styrenic resins was that they carried supplier guarantees of long-term supply and notification of change of up to 12 months. Customers can benefit from having a material supplier who thoroughly understands the regulatory environment, and can offer information about the products’ compliance with regulations, such as USP class VI, ISO 10993-5, FDA, and EU Food compliance. Offering such expertise is essential for suppliers to help customers navigate the regulatory intricacies associated with materials in medical devices.

This article was written by Alexander Silvestre, Global Director of Healthcare, Styrolution, Aurora, IL. For more information on Styrolution, visit http://info.hotims.com/55590-162 . MD&M East, Booth 2268. For more information on Microspec, Peterborough, NH, visit http://info.hotims.com/55590-193 . MD&M East, Booth 938.